Articulating implant connectors and related methods

ABSTRACT

Articulating implant connectors and related methods are disclosed herein. Exemplary connectors can include first and second bodies that are rotatable relative to one another about a rotation axis and selectively lockable to resist or prevent such rotation. Each of the bodies can be configured to couple to a rod or other fixation component, and the connector can be used to lock first and second rods together even when the rods are obliquely angled with respect to one another.

RELATED APPLICATION

The present application is a continuation of U.S. application Ser. No.15/471,075, filed Mar. 28, 2017, which is incorporated herein byreference in its entirety.

FIELD

Articulating implant connectors and related methods are disclosedherein.

BACKGROUND

Fixation systems can be used in orthopedic surgery to maintain a desiredspatial relationship between multiple bones or bone fragments. Forexample, various conditions of the spine, such as fractures,deformities, and degenerative disorders, can be treated by attaching aspinal fixation system to one or more vertebrae. Such systems typicallyinclude a spinal fixation element, such as a rigid or flexible rod orplate, that is coupled to the vertebrae by attaching the element tovarious anchoring devices, such as screws, hooks, or wires. Onceinstalled, the fixation system holds the vertebrae in a desired positionuntil healing or spinal fusion can occur, or for some other period oftime.

There are many instances in which it may be desirable to connectmultiple implants to each other. For example, some revision surgeriesinvolve extending a previously-installed construct to additionalvertebral levels by coupling a newly-installed spinal rod to apreviously-installed rod. By way of further example, aspects of thepatient's anatomy, the surgical technique used, or the desiredcorrection may require that multiple spinal rods be connected to oneanother. As yet another example, coupling multiple rods to one anothercan improve the overall strength and stability of an implantedconstruct.

There can be various difficulties associated with connecting multipleimplants to each other. The available space for the implanted constructcan often be very limited, particularly in the cervical area of thespine. Also, aligning and positioning implants and connectors in thesurgical wound may be challenging or cumbersome for the surgeon. Thereis a continual need for improved implant connectors and related methods.

SUMMARY

Articulating implant connectors and related methods are disclosedherein. Exemplary connectors can include first and second bodies thatare rotatable relative to one another about a rotation axis andselectively lockable to resist or prevent such rotation. Each of thebodies can be configured to couple to a rod or other fixation component,and the connector can be used to lock first and second rods togethereven when the rods are obliquely angled with respect to one another.

In some embodiments, a connector can include a first body that defines afirst rod-receiving recess, the first body having proximal and distalends that define a proximal-distal axis extending therebetween; a secondbody that defines a second rod-receiving recess, the second body havingproximal and distal ends that define a proximal-distal axis extendingtherebetween; a hinge pin that couples the first body to the secondbody, a central longitudinal axis of the hinge pin defining a rotationaxis about which the first and second bodies rotate relative to oneanother; and a fastener movable with respect to at least one of thefirst and second bodies to urge the first and second bodies towards oneanother along the rotation axis and thereby lock relative rotation ofthe first and second bodies about the rotation axis.

The fastener can secure a rod to one of the first and secondrod-receiving recesses. The fastener can be a first fastener configuredto secure a first rod within the first rod-receiving recess. Theconnector can include a second fastener configured to secure a secondrod in the second rod-receiving recess. The hinge pin can be formedintegrally with the first body. The hinge pin can be rotatable relativeto both of the first and second bodies. The first and second bodies caninclude respective bearing surfaces configured to bear against oneanother to lock relative rotation of the first and second bodies aboutthe rotation axis. The bearing surfaces can be defined by complementarymale and female structures of the first and second bodies. The firstbody can include a conical male projection, an outer surface of whichdefines the bearing surface of the first body. The second body caninclude a conical female recess, an inner surface of which defines thebearing surface of the second body. The bearing surfaces can eachinclude teeth or splines. The hinge pin can be received within a cavityformed in the first body or the second body. The hinge pin can translatelongitudinally within the cavity as the fastener is moved relative tosaid at least one of the first and second bodies. The proximal-distalaxes of the first and second bodies can be obliquely angled with respectto one another. A force applied by the fastener can be transferred tothe hinge pin through a saddle. The saddle can include a conical surfacethat engages and bears against a corresponding conical surface of thehinge pin to pull the first and second bodies towards one another. Thesaddle can include a keel extending distally therefrom. The keel can bereceived within a slot formed in the hinge pin. The keel can have abearing surface that engages and bears against a corresponding bearingsurface of the slot to pull the first and second bodies towards oneanother. The bearing surfaces of the keel and the slot can lie in planesthat are obliquely angled with respect to the rotation axis. The saddlecan include first and second keels defining a space therebetween inwhich a central rib of the hinge pin is received. The first and secondkeels can have bearing surfaces that engage and bear againstcorresponding bearing surface of the hinge pin. The hinge pin caninclude a rod seat formed therein. The rod seat can be configured suchthat urging a rod against the rod seat causes the hinge pin to translaterelative to at least one of the first and second bodies along therotation axis. The rod seat can be positioned relative to the firstrod-receiving recess such that a lateral sidewall of the rod seatinterferes with a rod as the rod is seated in the first rod-receivingrecess. The rod seat can be curved in multiple planes.

In some embodiments, a connector can include a first body that defines afirst rod-receiving recess; a hinge pin formed integrally with the firstbody and extending laterally therefrom to a free end; a second body thatdefines a second rod-receiving recess, the second body having a cavityin which the free end of the hinge pin is received to couple the secondbody to the first body such that the first and second bodies rotaterelative to one another about a rotation axis; a first fastenerconfigured to secure a first rod within the first rod-receiving recess;and a second fastener configured to secure a second rod within thesecond rod-receiving recess and to urge the first and second bodiestowards one another along the rotation axis to lock relative rotation ofthe first and second bodies about the rotation axis.

The second fastener can be configured to bear against a saddle disposedwithin the second rod-receiving recess to urge a bearing surface of thesaddle against a bearing surface of the hinge pin to move the first andsecond bodies towards one another. The second fastener can be configuredto bear against a rod disposed within the second rod-receiving recess tourge the rod against a rod seat of the hinge pin to move the first andsecond bodies towards one another.

In some embodiments, a surgical method can include inserting a first rodinto a first rod-receiving recess of a first body of a connector;inserting a second rod into a second rod-receiving recess of a secondbody of the connector, the second body being coupled to the first bodyby a hinge pin; rotating the first body relative to the second bodyabout a rotation axis defined by the hinge pin; moving a fastener withrespect to at least one of the first and second bodies to urge the firstand second bodies towards one another along the rotation axis andthereby lock relative rotation of the first and second bodies about therotation axis; and securing the first and second rods to an anatomy of apatient.

The first rod can be secured to a cervical spine of the patient by oneor more bone anchors and the second rod can be secured to a thoracicspine of the patient by one or more bone anchors. Rotating the firstbody relative to the second body can cause the first and second rods tobe obliquely angled with respect to one another. Moving the fastener canbe effective both to secure one of the first and second rods to theconnector and to lock rotation of the connector.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of a connector, shown with first andsecond rods;

FIG. 1B is an exploded perspective view of the connector of FIG. 1A;

FIG. 1C is a sectional side view of the connector and rods of FIG. 1A;

FIG. 1D is a partial exploded view of the connector of FIG. 1A;

FIG. 1E is a perspective view of a first body of the connector of FIG.1A;

FIG. 1F is another perspective view of the first body of FIG. 1E;

FIG. 1G is a perspective view of a first saddle of the connector of FIG.1A;

FIG. 1H is another perspective view of the first saddle of FIG. 1G;

FIG. 1I is a perspective view of a hinge pin of the connector of FIG.1A;

FIG. 1J is an end view of the hinge pin of FIG. 1I;

FIG. 1K is a side view of the hinge pin of FIG. 1I;

FIG. 1L is a top view of the hinge pin of FIG. 1I;

FIG. 2A is a perspective view of a connector, shown with first andsecond rods;

FIG. 2B is an exploded perspective view of the connector of FIG. 2A;

FIG. 2C is a sectional side view of the connector and rods of FIG. 2A;

FIG. 2D is a perspective view of a second body of the connector of FIG.2A;

FIG. 2E is another perspective view of the second body of FIG. 2A;

FIG. 3A is a perspective view of a connector, shown with first andsecond rods;

FIG. 3B is an exploded perspective view of the connector of FIG. 3A;

FIG. 3C is a sectional side view of the connector and rods of FIG. 3A;

FIG. 3D is a perspective view of a saddle of the connector of FIG. 3A;

FIG. 3E is a side view of the saddle of FIG. 3D;

FIG. 3F is another perspective view of the saddle of FIG. 3D;

FIG. 3G is a perspective view of a first body of the connector of FIG.3A;

FIG. 3H is a perspective view of a second body of the connector of FIG.3A;

FIG. 3I is a top view of an alternate first body of the connector ofFIG. 3A;

FIG. 3J is an end view of an alternate saddle of the connector of FIG.3A

FIG. 3K is a side view of the alternate first body of FIG. 3I;

FIG. 3L is a side view of the alternate saddle of FIG. 3J;

FIG. 4A is a perspective view of a connector, shown with first andsecond rods and with first and second fasteners of the connectoromitted;

FIG. 4B is an exploded perspective view of the connector of FIG. 4A;

FIG. 4C is a sectional side view of the connector of FIG. 4A;

FIG. 4D is a perspective view of a second body of the connector of FIG.4A;

FIG. 4E is a side view of a first body of the connector of FIG. 4A;

FIG. 4F is a perspective sectional view of the first body of theconnector of FIG. 4A; and

FIG. 5 is a perspective view of a human spine with a fixation systemattached thereto.

DETAILED DESCRIPTION

Articulating implant connectors and related methods are disclosedherein. Exemplary connectors can include first and second bodies thatare rotatable relative to one another about a rotation axis andselectively lockable to resist or prevent such rotation. Each of thebodies can be configured to couple to a rod or other fixation component,and the connector can be used to lock first and second rods togethereven when the rods are obliquely angled with respect to one another.

Certain exemplary embodiments will now be described to provide anoverall understanding of the principles of the structure, function,manufacture, and use of the devices and methods disclosed herein. One ormore examples of these embodiments are illustrated in the accompanyingdrawings. Those skilled in the art will understand that the devices andmethods specifically described herein and illustrated in theaccompanying drawings are non-limiting exemplary embodiments. Thefeatures illustrated or described in connection with one exemplaryembodiment may be combined with the features of other embodiments.

FIGS. 1A-1L illustrate an exemplary embodiment of a connector 100. Asshown, the connector 100 can include a first body 102 that defines afirst rod-receiving recess or channel 104 and a second body 106 thatdefines a second rod-receiving recess or channel 108. The first andsecond bodies 102, 106 can be connected to one another at least in partby a hinge pin 110. The hinge pin 110 can define a rotation axis A1about which the first and second bodies 102, 106 can rotate relative toone another. The connector 100 can include first and second fasteners112, 114 configured to secure respective first and second rods R1, R2 orother fixation elements to the connector 100.

At least one of the fasteners 112, 114 can further be configured to urgethe first and second bodies 102, 106 towards one another and therebylock relative rotation of the first and second bodies about the rotationaxis A1. For example, the first fastener 112 can be tightened to securea first rod R1 within the first body 102 and to apply a force to a firstramped, curved, or otherwise tapered surface 116 of the hinge pin 110 todraw the first and second bodies 102, 106 towards one another, lockingrotation therebetween. In the illustrated embodiment, a force applied bythe first fastener 112 is transferred to the hinge pin 110 through thefirst rod R1 and through a first saddle 118 disposed between the firstrod and the hinge pin. In other arrangements, the saddle 118 can beomitted and the first rod R1 can bear directly against the hinge pin110. In still further arrangements, the first fastener 112 can beardirectly against the saddle 118. For example, the first fastener 112 caninclude an outer set screw that bears against the saddle 118 to lockrelative rotation of the bodies 102, 106, and an inner set screw thatbears against the first rod R1 to secure the first rod to the connector100.

Similarly, the second fastener 114 can be tightened to secure a secondrod R2 within the second body 106 and to apply a force to a secondramped, curved, or otherwise tapered surface 120 of the hinge pin 110 todraw the first and second bodies 102, 106 towards one another, lockingrotation therebetween. In the illustrated embodiment, a force applied bythe second fastener 114 is transferred to the hinge pin 110 through thesecond rod R2 and through a second saddle 122 disposed between thesecond rod and the hinge pin. In other arrangements, the saddle 122 canbe omitted and the second rod R2 can bear directly against the hinge pin110. In still further arrangements, the second fastener 114 can beardirectly against the saddle 122. For example, the second fastener 114can include an outer set screw that bears against the saddle 122 to lockrelative rotation of the bodies 102, 106, and an inner set screw thatbears against the second rod R2 to secure the second rod to theconnector 100.

The geometries of the various components of the connector 100 can beconfigured such that tightening either of the fasteners 112, 114individually is effective to lock relative rotation between the bodies102, 106, or such that both fasteners 112, 114 must be tightened beforerelative rotation between the bodies 102, 106 is locked.

The ability to rotate the first and second bodies 102, 106 relative toone another about the rotation axis A1 can advantageously allow firstand second rods R1, R2 to be locked together even when the rods areobliquely angled with respect to one another, e.g., in the sagittalplane or in the coronal plane. The connector 100 can be particularlyuseful in connecting tandem rods of a spinal fixation construct acrossthe cervical-thoracic (CT) junction of a patient. For example, theconnector 100 can secure the rods R1, R2 in a laterally-offsetarrangement to accommodate the different screw trajectories that mayoccur at the CT junction. By way of further example, the ability of theconnector 100 to articulate can allow a cervical rod and a thoracic rodto be locked to one another at an oblique angle in the sagittal plane,e.g., to restore natural lordosis or kyphosis. The connector 100 canalso be particularly useful in spinal deformity correction and otherprocedures in which multiple angled rods are to be coupled to oneanother.

The first body 102 is shown in greater detail in FIGS. 1C, 1E, and 1F.The first body 102 can include proximal and distal ends 102 p, 102 dthat define a proximal-distal axis A2. The proximal end 102 p of thebody 102 can include a pair of spaced apart arms 124, 126 that definethe first rod-receiving recess 104 therebetween. A rod R1 disposed inthe first rod-receiving recess 104 can have a central longitudinal rodaxis A3. The first rod-receiving recess 104 can be open in a proximaldirection, such that a rod R1 can be inserted into the recess by movingthe rod distally with respect to the connector 100. Alternatively, thefirst rod-receiving recess 104 can be open in distal direction, open ina lateral direction, or closed such that the rod R1 must be translatedalong the axis A3 to insert the rod into the recess 104.

Each of the arms 124, 126 can extend from the distal portion 102 d ofthe body 102 to a free end. The outer surfaces of each of the arms 124,126 can include a feature (not shown), such as a recess, dimple, notch,projection, or the like, to facilitate coupling of the connector 100 tovarious instruments. For example, the outer surface of each arm 124, 126can include an arcuate groove at the respective free end of the arms forattaching the connector 100 to an extension tower or retractor. The arms124, 126 can include or can be coupled to extension or reduction tabs(not shown) that extend proximally from the body 102 to functionallyextend the length of the arms 124, 126. The extension tabs canfacilitate insertion and reduction of a rod or other implant, as well asinsertion and locking of the first fastener 112. The extension tabs canbe configured to break away or otherwise be separated from the arms 124,126.

The inner surfaces of each of the arms 124, 126 can be configured tomate with the first fastener 112. For example, the inner surfaces of thearms 124, 126 can include threads that correspond to external threadsformed on the first fastener 112. Accordingly, rotation of the firstfastener 112 with respect to the body 102 about the axis A2 can beeffective to translate the first fastener with respect to the bodyaxially along the axis A2.

The inner surfaces of each of the arms 124, 126 can include features forretaining the first saddle 118 within the first body 102 and/or forlimiting or preventing certain movement of the saddle with respect tothe body. For example, the arms 124, 126 can each include a recess 128configured to receive a corresponding projection 144 formed on thesaddle 118. Each recess 128 can define a distal-facing upper surfaceconfigured to limit proximal travel of the saddle 118 along the axis A2and a proximal-facing lower surface configured to limit distal travel ofthe saddle 118 along the axis A2. The recess 128 can extend through lessthan an entire width of the arm in which the recess is formed, such thatrotation of the saddle 118 relative to the body 102 about the axis A2 islimited or prevented when the projections 144 of the saddle are receivedwithin the recesses.

It will be appreciated that the illustrated retention features areexemplary, and that various other retention features can be used insteador in addition. For example, the structures can be reversed such thatthe body 102 includes projections received within corresponding recessesformed in the saddle 118. As another example, the saddle 118 and thebody 102 can include opposed grooves in which a snap ring or C-clip isreceived to retain the saddle to the body. As yet another example, thesaddle 118 and the hinge pin 110 can include opposed grooves in which asnap ring or C-clip is received to retain the saddle to the hinge pin.

The first body 102 can include an outer bearing surface 130 configuredto contact and bear against a corresponding bearing surface 140 of thesecond body 106. The respective bearing surfaces 130, 140 of the bodies102, 106 can bear against one another to lock relative rotation betweenthe bodies as they are urged towards one another. In the illustratedembodiment, the bearing surfaces 130, 140 of the first and second bodies102, 106 are opposed planar surfaces configured to frictionally-engageone another when the connector 100 is locked. It will be appreciated,however, that various other arrangements can be used instead or inaddition. For example, the bearing surfaces 130, 140 can include or canbe defined by complementary male and female structures of the first andsecond bodies 102, 106. In some embodiments, the first body 102 caninclude a conical male projection, an outer surface of which defines thebearing surface 130 of the first body, and the second body 106 caninclude a conical female recess, an inner surface of which defines thebearing surface 140 of the second body. As the projection of the firstbody 102 is urged into the recess of the second body 106, the conicalsurfaces wedge against one another to form a taper-lock connection.While conical surfaces are described in the example above, the male andfemale features can include concave or convex spherical surfaces,stepped surfaces, and so forth.

One or both of the bearing surfaces 130, 140 can include surfacefeatures for enhancing grip between the surfaces. For example, one orboth surfaces can include teeth, grooves, roughening, surface texturesor coatings, etc. In some embodiments, as shown in FIG. 1D, each bearingsurface 130, 140 can include a plurality of teeth that extend radiallyoutward from the rotation axis A1. The teeth can selectively interlockto maintain the bodies 102, 106 in one of a plurality of discreterotational positions relative to one another.

The distal end 102 d of the body 102 can define an interior cavity 132in which a first end of the hinge pin 110 can be received. The cavity132 can be open to the bearing surface 130 of the first body 102 andopen to the first rod-receiving recess 104 as shown. In someembodiments, the cavity 132 can be a blind bore formed in the bearingsurface 130 of the body 102 and intersecting with the firstrod-receiving recess 104. At least one dimension of the cavity 132 canbe greater than a corresponding dimension of the hinge pin 110 to allowthe hinge pin to translate within the cavity along the rotation axis A1.As described further below, the cavity 132 can be dimensioned to limitthe degree to which the body 102 can rotate relative to the hinge pin110 about the axis A1.

The second body 106 can be identical or substantially identical to thefirst body 102, or can have any of the features or variations describedabove with respect to the first body 102. Accordingly, only a briefdescription of the second body 106 is provided here for the sake ofbrevity. The second body 106 can include proximal and distal ends 106 p,106 d that define a proximal-distal axis A4. The proximal end 106 p ofthe body 106 can include a pair of spaced apart arms 134, 136 thatdefine the second rod-receiving recess 108 therebetween. A rod R2disposed in the second rod-receiving recess 108 can have a centrallongitudinal rod axis A5. The second rod-receiving recess 108 can beopen in a proximal direction, such that a rod R2 can be inserted intothe recess by moving the rod distally with respect to the connector 100.Alternatively, the second rod-receiving recess 108 can be open in distaldirection, open in a lateral direction, or closed such that the rod R2must be translated along the axis A5 to insert the rod into the recess108.

Each of the arms 134, 136 can include features 138 for retaining thesaddle 122 within the body 106. The second body 106 can include an outerbearing surface 140 configured to contact and bear against the outerbearing surface 130 of the first body 102. The distal end 106 d of thesecond body 106 can define an interior cavity 142 in which a second endof the hinge pin 110 can be received. The cavity 142 can be open to thebearing surface 140 of the second body 106 and open to the second rodrecess 108 as shown. In some embodiments, the cavity 142 can be a blindbore formed in the bearing surface 140 of the body 106 and intersectingwith the second rod recess 108. At least one dimension of the cavity 142can be greater than a corresponding dimension of the hinge pin 110 toallow the hinge pin to translate within the cavity along the rotationaxis A1. As described further below, the cavity 142 can be dimensionedto limit the degree to which the body 106 can rotate relative to thehinge pin 110 about the axis A1.

The bodies 102, 106 of the connector 100 can include various featuresfor decreasing or increasing the center-to-center offset between thefirst and second rods R1, R2 when the rods are locked to the connector.In the illustrated embodiment, the bearing surfaces 130, 140 of thefirst and second bodies 102, 106 are obliquely angled with respect tothe bodies' respective proximal-distal axes A2, A4. Accordingly, therods R1, R2 move towards one another as they are advanced distally intothe connector 100. This can advantageously reduce the center-to-centeroffset of the rods R1, R2, while preserving sufficient materialthickness at the proximal ends of the bodies 102, 106 to withstand therelatively high forces subjected to the connector 100 during rodreduction, fastener tightening, and/or post-operative patient movement.

As another example, the bearing surfaces 130, 140 of the bodies 102, 106can be parallel to the proximal-distal axes A2, A4, and instead the rodrecesses 104, 108 can be obliquely angled or can follow a curved pathwith respect to the proximal-distal axes to bring the rods R1, R2 closertogether.

As another example, the axis along which the first fastener 112 advancesas it is tightened can be offset laterally from the first rod axis A3when the first rod R1 is fully seated in the recess 104, or can beobliquely angled with respect to the proximal-distal axis A2 of thefirst body 102. Alternatively, or in addition, the axis along which thesecond fastener 114 advances as it is tightened can be offset laterallyfrom the second rod axis A5 when the second rod R2 is fully seated inthe recess 108, or can be obliquely angled with respect to theproximal-distal axis A4 of the second body 106.

The rotation axis A1 of the connector 100 can be perpendicular to therod axis A3 and perpendicular to the rod axis A5. The rotation axis A1can be perpendicular to the proximal-distal axis A2 of the first body,or can be obliquely angled with respect to the axis A2. The rotationaxis A1 can be perpendicular to the proximal-distal axis A4 of thesecond body, or can be obliquely angled with respect to the axis A4. Theproximal-distal axes A2, A4 of the bodies 102, 106 can be parallel toone another or can extend at an oblique angle with respect to oneanother.

The first saddle 118 is shown in greater detail in FIGS. 1C, 1G, and 1H.The saddle 118 can be positioned within the body 102. The saddle 118 canbe configured to translate within the body 102 along the axis A2, e.g.,between proximal and distal limits defined by the interaction betweenthe recesses 128 of the body 102 and projections 144 formed on thesaddle.

The saddle 118 can be generally cylindrical with first and second arms146, 148 extending in a proximal direction to respective free ends ofthe arms. The first and second arms 146, 148 can be aligned with thefirst and second arms 124, 126 of the body 102 such that a recessdefined therebetween is aligned with the first rod-receiving recess 104.Accordingly, the first rod R1 can be simultaneously cradled between thearms 146, 148 of the saddle 118 and the arms 124, 126 of the body 102when the rod is disposed in the first rod-receiving recess 104. Thefirst and second arms 146, 148 of the saddle 118 can include projections144 extending radially outward therefrom and configured to be receivedwithin the recesses 128 of the first body 102.

The distal-facing surface of the saddle 118 can define a recess 150configured to receive at least a portion of the hinge pin 110. In theillustrated embodiment, the recess 150 is semi-cylindrical. The depth ofthe recess 150 can increase along the length of the recess as shown toaccount for a body geometry in which the proximal-distal axis A2 of thebody is obliquely angled with respect to the rotation axis A1 of thehinge pin 110.

The saddle 118 can include one or more ramped, curved, or otherwisetapered surfaces configured to contact and bear against a counterpartsurface of the hinge pin 110. For example, a depression formed in theouter surface of the first arm 146 of the saddle 118 can define a firstbearing surface 152 that is a section of a cone. A depression formed inthe outer surface of the second arm 148 of the saddle 118 can define asecond bearing surface 154 that is a section of a cone.

The second saddle 122 can be identical or substantially identical to thefirst saddle 118, or can have any of the features or variationsdescribed above with respect to the first saddle 118. Accordingly, onlya brief description of the second saddle 122 is provided here for thesake of brevity. The second saddle 122 can be positioned within the body106. The saddle 122 can be configured to translate within the body 106along the axis A4, e.g., between proximal and distal limits defined bythe interaction between the recesses 138 of the body and projections 156formed on the saddle.

The saddle 122 can be generally cylindrical with first and second arms158, 160 extending in a proximal direction to respective free ends ofthe arms. The first and second arms 158, 160 can be aligned with thefirst and second arms 134, 136 of the body 106 such that a recessdefined therebetween is aligned with the second rod-receiving recess108. Accordingly, the second rod R2 can be simultaneously cradledbetween the arms 158, 160 of the saddle 122 and the arms 134, 136 of thebody 106 when the rod is disposed in the second rod-receiving recess108. The first and second arms 158, 160 of the saddle 122 can includeprojections 156 extending radially outward therefrom and configured tobe received within the recesses 138 of the second body 106.

The distal-facing surface of the saddle 122 can define a recess 162configured to receive at least a portion of the hinge pin 110. In theillustrated embodiment, the recess 162 is semi-cylindrical. The depth ofthe recess 162 can increase along the length of the recess as shown toaccount for a body geometry in which the proximal-distal axis A4 of thebody 106 is obliquely angled with respect to the rotation axis A1 of thehinge pin 110.

The saddle 122 can include one or more ramped, curved, or otherwisetapered surfaces configured to contact and bear against a counterpartsurface of the hinge pin 110. For example, a depression formed in theouter surface of the first arm 158 of the saddle 122 can define a firstbearing surface 164 that is a section of a cone. A depression formed inthe outer surface of the second arm 160 of the saddle 122 can define abearing surface 166 that is a section of a cone.

The first fastener 112 can include an exterior thread configured to matewith the interior threads formed on the arms 124, 126 of the body 102 toallow the first fastener to be advanced or retracted along the axis A2with respect to the body by rotating the first fastener about the axisA2. The first fastener 112 can include a driving interface 168configured to receive a driver for applying a rotational force to thefirst fastener about the axis A2. The distal surface of the firstfastener 112 can be configured to contact and bear against a rod R1disposed in the first rod-receiving 104 recess to lock the rod to theconnector 100. When tightened against the rod R1, the first fastener 112can prevent the rod from translating relative to the connector 100 alongthe axis A3 and/or from rotating with respect to the connector about theaxis A3. While a unitary set screw 112 is shown, it will be appreciatedthat other fasteners can be used instead or addition, such as a closurecap that advances and locks by quarter-turn rotation, a closure cap thatslides in laterally without rotating, a nut that threads onto anexterior of the body, or a dual-component set screw withindependently-rotatable inner and outer members, the inner member actingon the rod R1 and the outer member acting on the saddle 118.

The second fastener 114 can include an exterior thread configured tomate with the interior threads formed on the arms 134, 136 of the secondbody 106 to allow the second fastener to be advanced or retracted alongthe axis A4 with respect to the body by rotating the second fastenerabout the axis A4. The second fastener 114 can include a drivinginterface 170 configured to receive a driver for applying a rotationalforce to the second fastener 114 about the axis A4. The distal surfaceof the second fastener 114 can be configured to contact and bear againsta rod R2 disposed in the second rod-receiving 108 recess to lock the rodto the connector 100. When tightened against the rod R2, the secondfastener 114 can prevent the rod from translating relative to theconnector 100 along the axis A5 and/or from rotating with respect to theconnector about the axis A5. While a unitary set screw 114 is shown, itwill be appreciated that other fasteners can be used instead oraddition, such as a closure cap that advances and locks by quarter-turnrotation, a closure cap that slides in laterally without rotating, a nutthat threads onto an exterior of the body, or a dual-component set screwwith independently-rotatable inner and outer members, the inner memberacting on the rod R2 and the outer member acting on the saddle 122.

The hinge pin 110 is shown in greater detail in FIGS. 1I-1L. As shown,the hinge pin 110 can include opposed first and second ends that definea central longitudinal axis A6 extending therebetween. The longitudinalaxis A6 can be collinear with the rotation axis A1 of the connector 100.The hinge pin 110 can be formed as a substantially cylindrical shaftwith one or more protrusions 172 extending radially outward therefrom.One or both side surfaces of the protrusions 172 can be ramped, curved,or otherwise tapered and configured to contact and bear againstcounterpart surfaces of the saddles 118, 122 or, in embodiments in whichthe saddles are omitted, against counterpart surfaces of the rods R1,R2. The illustrated hinge pin 110 includes at least first and secondprotrusion surfaces 116, 120 that each form sections of respectivecones. The middle protrusion 172 of the hinge pin 110 can help keep thehinge pin centered in the cavities 132, 142 and maintain the bodies 102,106 in a position in which the bearing surfaces 130, 140 are parallel.

The protrusions 172 can extend around less than an entire circumferenceof the hinge pin 110, such that the protrusions have a non-cylindricalcross-section in a plane transverse to the axis A6. For example, asshown in FIG. 1J, each protrusion can define a lobe shape with first andsecond flat segments 172A, 172B joined by an arc 172C. The cavities 132,142 formed in the bodies 102, 106 can have a corresponding shape, onlywith an arc that extends a greater degree about the circumference of thehinge pin 110. Accordingly, when the protrusions 172 are received withinthe cavities 132, 142, the degree to which the bodies 102, 106 are ableto rotate relative to the hinge pin 110 about the axis A1 is limited tothe difference between the arc length of the protrusions and the arclength of the cavity.

The connector 100 can be assembled by inserting one end of the hinge pin110 into the cavity 132 of the first body 102 and the other end of thehinge pin into the cavity 142 of the second body 106. The saddles 118,122 can be inserted into the proximal ends of the bodies 102, 106 andadvanced distally until the projections 144, 156 of the saddles snapinto the grooves 128, 138 of the bodies to retain the saddles therein.At this stage of assembly, even before locking rods within the connector100, the saddles 118, 122 can interfere with the protrusions 172 of thehinge pin 110 to prevent the hinge pin from being removed from either ofthe first and second bodies 102, 106.

A first rod R1 can be seated in the first rod recess 104 and secured tothe connector 100 by tightening the first fastener 112. As the firstfastener 112 is tightened, the first rod R1 can be urged distallyagainst the saddle 118, in turn urging the saddle distally against thehinge pin 110. As the saddle 118 is urged distally, the female conicalsurface 152 of the saddle bears against the male conical surface 116 ofthe hinge pin protrusion 172, applying a force to the hinge pin 110 thaturges the hinge pin deeper into the cavity 132.

A second rod R2 can be seated in the second rod recess 108 and securedto the connector 100 by tightening the second fastener 114. As thesecond fastener 114 is tightened, the second rod R2 can be urgeddistally against the saddle 122, in turn urging the saddle distallyagainst the hinge pin 110. As the saddle 122 is urged distally, thefemale conical surface 166 of the saddle bears against the male conicalsurface 120 of the hinge pin protrusion 172, applying a force to thehinge pin 110 that urges the hinge pin deeper into the cavity 142.

Before fully tightening one or both fasteners 112, 114, the bodies 102,106 can be rotated relative to one another about the axis A1 as desiredby the user. The fasteners 112, 114 can then be tightened to lock suchrelative rotation. In particular, the opposing forces applied to thehinge pin 110 by the saddles 118, 122 as the fasteners 112, 114 aretightened can cause the bodies 102, 106 to translate relative to oneanother along the axis A1, urging the bearing surfaces 130, 140 of thebodies into engagement with each other. Friction, mechanical interlock,or other forces between the bearing surfaces 130, 140 can be effectiveto lock relative rotation of the bodies 102, 106 about the axis A1.

FIGS. 2A-2E illustrate an exemplary embodiment of a connector 200. Asshown, the connector 200 can include a first body 202 that defines afirst rod-receiving recess or channel 204 and a second body 206 thatdefines a second rod-receiving recess or channel 208. The first andsecond bodies 202, 206 can be connected to one another at least in partby a hinge pin 210. The hinge pin 210 can define a rotation axis A1about which the first and second bodies 202, 206 can rotate relative toone another. The connector 200 can include first and second fasteners212, 214 configured to secure respective first and second rods R1, R2 orother fixation elements to the connector 200.

At least one of the fasteners 212, 214 can further be configured to urgethe first and second bodies 202, 206 towards one another and therebylock relative rotation of the first and second bodies about the rotationaxis A1. For example, the first fastener 212 can be tightened to securea first rod R1 within the first body 202 and to apply a force to a firstramped, curved, or otherwise tapered surface 216 of the hinge pin 210 todraw the first and second bodies 202, 206 towards one another, lockingrotation therebetween. In the illustrated embodiment, a force applied bythe first fastener 212 is transferred to the hinge pin 210 through thefirst rod R1. In other arrangements, a saddle of the type describedabove can be disposed between the first rod R1 and the hinge pin 210. Instill further arrangements, the first fastener 212 can bear directlyagainst a saddle. For example, the first fastener 212 can include anouter set screw that bears against a saddle to lock relative rotation ofthe bodies 202, 206, and an inner set screw that bears against the firstrod R1 to secure the first rod to the connector 200.

The second fastener 214 can be tightened to secure a second rod R2within the second body 206. The second fastener 214 can bear directlyagainst the second rod R2, or against an intermediate rod pusher 222 asshown.

The ability to rotate the first and second bodies 202, 206 relative toone another about the rotation axis A1 can advantageously allow firstand second rods R1, R2 to be locked together even when the rods areobliquely angled with respect to one another, e.g., in the sagittalplane or in the coronal plane. The connector 200 can be particularlyuseful in connecting tandem rods of a spinal fixation construct acrossthe cervical-thoracic (CT) junction of a patient. For example, theconnector 200 can secure the rods R1, R2 in a laterally-offsetarrangement to accommodate the different screw trajectories that mayoccur at the CT junction. By way of further example, the ability of theconnector 200 to articulate can allow a cervical rod and a thoracic rodto be locked to one another at an oblique angle in the sagittal plane,e.g., to restore natural lordosis or kyphosis. The connector 200 canalso be particularly useful in spinal deformity correction and otherprocedures in which multiple angled rods are to be coupled to oneanother.

The first body 202 can include proximal and distal ends 202 p, 202 dthat define a proximal-distal axis A2. The proximal end 202 p of thebody 202 can include a pair of spaced apart arms 224, 226 that definethe first rod-receiving recess 204 therebetween. A rod R1 disposed inthe first rod-receiving recess 204 can have a central longitudinal rodaxis A3. The first rod-receiving recess 204 can be open in a proximaldirection, such that a rod R1 can be inserted into the recess by movingthe rod distally with respect to the connector 200. Alternatively, thefirst rod-receiving recess 204 can be open in distal direction, open ina lateral direction, or closed such that the rod R1 must be translatedalong the axis A3 to insert the rod into the recess 204.

Each of the arms 224, 226 can extend from the distal portion 202 d ofthe body 202 to a free end. The outer surfaces of each of the arms 224,226 can include a feature (not shown), such as a recess, dimple, notch,projection, or the like, to facilitate coupling of the connector 200 tovarious instruments. For example, the outer surface of each arm 224, 226can include an arcuate groove at the respective free end of the arms forattaching the connector 200 to an extension tower or retractor. The arms224, 226 can include or can be coupled to extension or reduction tabs(not shown) that extend proximally from the body 202 to functionallyextend the length of the arms 224, 226. The extension tabs canfacilitate insertion and reduction of a rod or other implant, as well asinsertion and locking of the first fastener 212. The extension tabs canbe configured to break away or otherwise be separated from the arms 224,226.

The inner surfaces of each of the arms 224, 226 can be configured tomate with the first fastener 212. For example, the inner surfaces of thearms 224, 226 can include threads that correspond to external threadsformed on the first fastener 212. Accordingly, rotation of the firstfastener 212 with respect to the body 202 about the axis A2 can beeffective to translate the first fastener with respect to the bodyaxially along the axis A2.

The first body 202 can include an outer bearing surface 230 configuredto contact and bear against a corresponding bearing surface 240 of thesecond body 206. The respective bearing surfaces 230, 240 of the bodies202, 206 can bear against one another to lock relative rotation betweenthe bodies as they are urged towards one another. In the illustratedembodiment, the bearing surfaces 230, 240 of the first and second bodies202, 206 are defined by complementary male and female structures of thefirst and second bodies 202, 206. As shown, the first body 202 caninclude a conical male projection, an outer surface of which defines thebearing surface 230 of the first body, and the second body 206 caninclude a conical female recess, an inner surface of which defines thebearing surface 240 of the second body. As the projection of the firstbody 202 is urged into the recess of the second body 206, the conicalsurfaces 230, 240 wedge against one another to form a taper-lockconnection. While conical surfaces are described in the example above,the male and female features can include concave or convex sphericalsurfaces, stepped surfaces, and so forth. It will be appreciated thatvarious other arrangements can be used instead or in addition, such asopposed planar surfaces configured to frictionally-engage one another asin the connector 100 described above.

One or both of the bearing surfaces 230, 240 can include surfacefeatures for enhancing grip between the surfaces. For example, one orboth surfaces can include teeth, grooves, roughening, surface texturesor coatings, etc. In some embodiments, each bearing surface 230, 240 caninclude a plurality of teeth that extend radially outward from therotation axis A1. The teeth can selectively interlock to maintain thebodies 202, 206 in one of a plurality of discrete rotational positionsrelative to one another.

The distal end 202 d of the body 202 can define an interior cavity 232in which a first end of the hinge pin 210 can be received. The cavity232 can be open to the bearing surface 230 of the first body 202 andopen to the first rod-receiving recess 204 as shown. In someembodiments, the cavity 232 can be a blind bore formed in the bearingsurface 230 of the body 202 and intersecting with the firstrod-receiving recess 204. At least one dimension of the cavity 232 canbe greater than a corresponding dimension of the hinge pin 210 to allowthe hinge pin to translate within the cavity along the rotation axis A1.

The second body 202 is shown in greater detail in FIGS. 2C, 2D, and 2E.The second body 206 can include proximal and distal ends 206 p, 206 dthat define a proximal-distal axis A4. The body 206 can include a pairof spaced apart arms 234, 236 that define the second rod-receivingrecess 208 therebetween. A rod R2 disposed in the second rod-receivingrecess 208 can have a central longitudinal rod axis A5. The secondrod-receiving recess 208 can be open in a lateral direction, as shown,such that a rod R2 can be inserted into the recess by moving the rodlaterally with respect to the connector 200. Alternatively, the secondrod-receiving recess 208 can be open in a proximal direction, open in adistal direction, or closed such that the rod R2 must be translatedalong the axis A5 to insert the rod into the recess 208.

The second body 206 can include an outer bearing surface 240 configuredto contact and bear against the outer bearing surface 230 of the firstbody 202. The second body 206 can define an interior cavity 242 in whicha second end of the hinge pin 210 can be received. The cavity 242 can beopen to the bearing surface 240 of the second body 206 and open to thesecond rod recess 208 as shown. The cavity 242 can include a shoulder274 configured to limit translation of the hinge pin 210 relative to thebody 206 along the axis A1.

A rod pusher 222 can be disposed within the cavity 242 and can beconfigured to bear against the second rod R2. The rod pusher 222 can becoupled to the second body 206 by a bias element configured to bias therod pusher towards the rod R2, e.g., to provide a “snap and drag” effectwhen seating the rod in the second recess 208. Further details on suchfeatures can be found in U.S. application Ser. No. 15/158,127 filed onMay 18, 2016 and entitled “IMPLANT CONNECTORS AND RELATED METHODS,” nowissued as U.S. Pat. No. 10,517,647, which is hereby incorporated byreference in its entirety.

At least one of the arms 234, 236 of the second body 206 can include anopening 276 configured to receive the second fastener 214 therein. Forexample, as shown, the first arm 234 can include a threaded opening 276in which the second fastener 214 can be advanced to urge the rod pusher222 against a second rod R2 seated in the second rod-receiving recess208.

The bodies 202, 206 of the connector 200 can include various featuresfor decreasing or increasing the center-to-center offset between thefirst and second rods R1, R2 when the rods are locked to the connector.In the illustrated embodiment, the outer surface of the first body 202that opposes the second body 206 is obliquely angled with respect to theproximal-distal axis A2. Accordingly, the rods R1, R2 move towards oneanother as they are advanced into the connector 200. This canadvantageously reduce the center-to-center offset of the rods R1, R2,while preserving sufficient material thickness at the proximal end ofthe first body 202 to withstand the relatively high forces subjected tothe connector 200 during rod reduction, fastener tightening, and/orpost-operative patient movement.

As another example, the opposing outer surfaces of the bodies 202, 206can be parallel to the proximal-distal axes A2, A4, and instead the rodrecesses 204, 208 can be obliquely angled or can follow a curved pathwith respect to the proximal-distal axes to bring the rods R1, R2 closertogether.

As another example, the axis along which the first fastener 212 advancesas it is tightened can be offset laterally from the first rod axis A3when the first rod R1 is fully seated in the recess 204, or can beobliquely angled with respect to the proximal-distal axis A2 of thefirst body 202. Alternatively, or in addition, the axis along which thesecond fastener 214 advances as it is tightened can be offset laterallyfrom the second rod axis A5 when the second rod R2 is fully seated inthe recess 208, or can be obliquely angled with respect to theproximal-distal axis A4 of the second body 206.

The rotation axis A1 of the connector 200 can be perpendicular to therod axis A3 and perpendicular to the rod axis A5. The rotation axis A1can be perpendicular to the proximal-distal axis A2 of the first body,or can be obliquely angled with respect to the axis A2. The rotationaxis A1 can be perpendicular to the proximal-distal axis A4 of thesecond body, or can be obliquely angled with respect to the axis A4. Theproximal-distal axes A2, A4 of the bodies 202, 206 can be parallel toone another or can extend at an oblique angle with respect to oneanother.

The first fastener 212 can include an exterior thread configured to matewith the interior threads formed on the arms 224, 226 of the body 202 toallow the first fastener to be advanced or retracted along the axis A2with respect to the body by rotating the first fastener about the axisA2. The first fastener 212 can include a driving interface 268configured to receive a driver for applying a rotational force to thefirst fastener about the axis A2. The distal surface of the firstfastener 212 can be configured to contact and bear against a rod R1disposed in the first rod-receiving 204 recess to lock the rod to theconnector 200. When tightened against the rod R1, the first fastener 212can prevent the rod from translating relative to the connector 200 alongthe axis A3 and/or from rotating with respect to the connector about theaxis A3. While a unitary set screw 212 is shown, it will be appreciatedthat other fasteners can be used instead or addition, such as a closurecap that advances and locks by quarter-turn rotation, a closure cap thatslides in laterally without rotating, a nut that threads onto anexterior of the body, or a dual-component set screw withindependently-rotatable inner and outer members, the inner member actingon the rod R1 and the outer member acting on a saddle of the typedescribed above.

The second fastener 214 can include an exterior thread configured tomate with the interior threads formed in the first arm 234 of the secondbody 206 to allow the second fastener to be advanced or retracted alongthe axis A4 with respect to the body by rotating the second fastenerabout the axis A4. The second fastener 214 can include a drivinginterface 270 configured to receive a driver for applying a rotationalforce to the second fastener 214 about the axis A4. The distal surfaceof the second fastener 214 can be configured to contact and bear againstthe rod pusher 222 or, in embodiments in which the rod pusher isomitted, against a rod R2 disposed in the second rod-receiving 208recess to lock the rod to the connector 200. When tightened, the secondfastener 214 can prevent the rod R2 from translating relative to theconnector 200 along the axis A5 and/or from rotating with respect to theconnector about the axis A5. While a unitary set screw 214 is shown, itwill be appreciated that other fasteners can be used instead oraddition, such as a closure cap that advances and locks by quarter-turnrotation, a closure cap that slides in laterally without rotating, or anut that threads onto an exterior of the body.

The hinge pin 210 can include opposed first and second ends that definea central longitudinal axis A6 extending therebetween. The longitudinalaxis A6 can be collinear with the rotation axis A1 of the connector 200.The hinge pin 210 can be formed as a substantially cylindrical shaft.The portion of the hinge pin 210 received within the first body 202 caninclude a rod seat 278. The portion of the hinge pin 210 received withinthe second body 206 can include a protrusion 272 extending radiallyoutward therefrom.

The protrusion 272 can be seated in and can bear against the shoulder274 formed in the second body 206. Accordingly, lateral translation ofthe hinge pin 210 along the axis A1, e.g., as the first rod R1 is urgedagainst the hinge pin, can cause the second body 206 to be urged towardsthe first body to lock relative rotation therebetween. The rod seat 278can be ramped, curved, or otherwise tapered and configured to contactand bear against the first rod R1. The rod seat 278 can have a widthparallel to the axis A1 that is greater than the diameter of the firstrod R1 and/or greater than the width of the first rod-receiving recess204. The rod seat 278 can be located along the length of the hinge pin210 at a position in which a lateral sidewall 216 of the rod seatinterferes with a rod R1 as the rod is seated in the first rod-receivingrecess 204. As the rod R1 is advanced into the first rod-receivingrecess 204, it can bear against the lateral sidewall 216 of the rod seat278 to cause the hinge pin 210 to translate laterally along the axis A1,pulling the second body 206 towards the first body 202 to lock relativerotation therebetween. The hinge pin 210 can be rotatable relative tothe first and second bodies 202, 206 about the axis A1, such that thefloor of the rod seat 278 remains aligned with a floor of the firstrod-receiving recess 204 or is moved into such alignment automaticallyas a rod R1 is seated therein. Prior to seating the first rod R1, thehinge pin 210 can be retained within the cavity 232 of the first body202 using various techniques, such as swaging or a retention pin thatlimits axial translation of the hinge pin 210 relative to the bodywithout limiting rotation of the hinge pin relative to the body aboutthe axis A1.

The connector 200 can be assembled by inserting the hinge pin 210through the cavity 242 of the second body 206 to seat the protrusion 272of the hinge pin against the shoulder 274 and then installing the rodpusher 222 within the second body to retain the hinge pin therein. Thefree end of the hinge pin 210 can then be inserted into the cavity 232of the first body 202 and retained therein with a retention feature ofthe type described above. At this stage of assembly, even before lockingrods within the connector 200, the hinge pin 210 can be prevented frombeing removed from either of the first and second bodies 202, 206.

A second rod R2 can be seated in the second rod recess 208 and securedto the connector 200 by tightening the second fastener 214. As thesecond fastener 214 is tightened, the rod pusher 222 can be urgeddistally against the second rod R2 to lock the rod to the connector 200.The second body 206 can remain free to rotate relative to the first body202 about the axis A1 even after the second rod R2 is locked to theconnector 200.

A first rod R1 can be seated in the first rod recess 204 and secured tothe connector 200 by tightening the first fastener 212. As the firstfastener 212 is tightened, the first rod R1 can be urged distallyagainst the rod seat 278 of the hinge pin 210, applying a force to thehinge pin that urges the hinge pin deeper into the cavity 232.

Before fully tightening one or both fasteners 212, 214, the bodies 202,206 can be rotated relative to one another about the axis A1 as desiredby the user. The fastener 212 can then be tightened to lock suchrelative rotation. In particular, the force applied to the hinge pin 210by the first rod R1 when the fastener 212 is tightened can cause thebodies 202, 206 to translate relative to one another along the axis A1,urging the bearing surfaces 230, 240 of the bodies into engagement witheach other. Friction, mechanical interlock, or other forces between thebearing surfaces 230, 240 can be effective to lock relative rotation ofthe bodies 202, 206 about the axis A1. It will be appreciated that theconnector 200 can allow locking of the second rod R2 to the connectorand locking of the rotational degree-of-freedom of the connector to beperformed independently of one another.

FIGS. 3A-3L illustrate an exemplary embodiment of a connector 300. Asshown, the connector 300 can include a first body 302 that defines afirst rod-receiving recess or channel 304 and a second body 306 thatdefines a second rod-receiving recess or channel 308. The first andsecond bodies 302, 306 can be connected to one another at least in partby a hinge pin 310. The hinge pin 310 can define a rotation axis A1about which the first and second bodies 302, 306 can rotate relative toone another. The connector 300 can include first and second fasteners312, 314 configured to secure respective first and second rods R1, R2 orother fixation elements to the connector 300.

At least one of the fasteners 312, 314 can further be configured to urgethe first and second bodies 302, 306 towards one another and therebylock relative rotation of the first and second bodies about the rotationaxis A1. For example, the second fastener 314 can be tightened to securea second rod R2 within the second body 306 and to apply a force to aramped, curved, or otherwise tapered surface 320 of the hinge pin 310 todraw the first and second bodies 302, 306 towards one another, lockingrotation therebetween. In the illustrated embodiment, a force applied bythe second fastener 314 is transferred to the hinge pin 310 through thesecond rod R2 and through a saddle 322 disposed between the second rodand the hinge pin. In other arrangements, the saddle 322 can be omittedand the second rod R2 can bear directly against the hinge pin 310. Instill further arrangements, the second fastener 314 can bear directlyagainst the saddle 322. For example, the second fastener 314 can includean outer set screw that bears against the saddle 322 to lock relativerotation of the bodies 302, 306, and an inner set screw that bearsagainst the second rod R2 to secure the second rod to the connector 300.

The first fastener 312 can be tightened to secure a first rod R1 withinthe first body 302. The first fastener 312 can bear directly against thefirst rod R1 as shown, or against an intermediate rod pusher of the typedescribed above with respect to the connector 200.

The ability to rotate the first and second bodies 302, 306 relative toone another about the rotation axis A1 can advantageously allow firstand second rods R1, R2 to be locked together even when the rods areobliquely angled with respect to one another, e.g., in the sagittalplane or in the coronal plane. The connector 300 can be particularlyuseful in connecting tandem rods of a spinal fixation construct acrossthe cervical-thoracic (CT) junction of a patient. For example, theconnector 300 can secure the rods R1, R2 in a laterally-offsetarrangement to accommodate the different screw trajectories that mayoccur at the CT junction. By way of further example, the ability of theconnector 300 to articulate can allow a cervical rod and a thoracic rodto be locked to one another at an oblique angle in the sagittal plane,e.g., to restore natural lordosis or kyphosis. The connector 300 canalso be particularly useful in spinal deformity correction and otherprocedures in which multiple angled rods are to be coupled to oneanother.

The first body 302 is shown in greater detail in FIGS. 3C and 3G. Thefirst body 302 can include proximal and distal ends 302 p, 302 d thatdefine a proximal-distal axis A2. The proximal end 302 p of the body 302can include a pair of spaced apart arms 324, 326 that define the firstrod-receiving recess 304 therebetween. A rod R1 disposed in the firstrod-receiving recess 304 can have a central longitudinal rod axis A3.The first rod-receiving recess 304 can be open in a proximal direction,such that a rod R1 can be inserted into the recess by moving the roddistally with respect to the connector 300. Alternatively, the firstrod-receiving recess 304 can be open in distal direction, open in alateral direction, or closed such that the rod R1 must be translatedalong the axis A3 to insert the rod into the recess 304.

Each of the arms 324, 326 can extend from the distal portion 302 d ofthe body 302 to a free end. The outer surfaces of each of the arms 324,326 can include a feature (not shown), such as a recess, dimple, notch,projection, or the like, to facilitate coupling of the connector 300 tovarious instruments. For example, the outer surface of each arm 324, 326can include an arcuate groove at the respective free end of the arms forattaching the connector 300 to an extension tower or retractor. The arms324, 326 can include or can be coupled to extension or reduction tabs(not shown) that extend proximally from the body 302 to functionallyextend the length of the arms 324, 326. The extension tabs canfacilitate insertion and reduction of a rod or other implant, as well asinsertion and locking of the first fastener 312. The extension tabs canbe configured to break away or otherwise be separated from the arms 324,326.

The inner surfaces of each of the arms 324, 326 can be configured tomate with the first fastener 312. For example, the inner surfaces of thearms 324, 326 can include threads that correspond to external threadsformed on the first fastener 312. Accordingly, rotation of the firstfastener 312 with respect to the body 302 about the axis A2 can beeffective to translate the first fastener with respect to the bodyaxially along the axis A2.

The first body 302 can include an outer bearing surface 330 configuredto contact and bear against a corresponding bearing surface 340 of thesecond body 306. The respective bearing surfaces 330, 340 of the bodies302, 306 can bear against one another to lock relative rotation betweenthe bodies as they are urged towards one another. In the illustratedembodiment, the bearing surfaces 330, 340 of the first and second bodies302, 306 are defined by complementary male and female structures of thefirst and second bodies 302, 306. As shown, the first body 302 caninclude a conical male projection, an outer surface of which defines thebearing surface 330 of the first body, and the second body 306 caninclude a conical female recess, an inner surface of which defines thebearing surface 340 of the second body. As the projection of the firstbody 302 is urged into the recess of the second body 306, the conicalsurfaces 330, 340 wedge against one another to form a taper-lockconnection. While conical surfaces are described in the example above,the male and female features can include concave or convex sphericalsurfaces, stepped surfaces, and so forth. It will be appreciated thatvarious other arrangements can be used instead or in addition, such asopposed planar surfaces configured to frictionally-engage one another asin the connector 100 described above.

One or both of the bearing surfaces 330, 340 can include surfacefeatures for enhancing grip between the surfaces. For example, one orboth surfaces can include teeth, grooves, roughening, surface texturesor coatings, etc. In some embodiments, each bearing surface 330, 340 caninclude a plurality of teeth that extend radially outward from therotation axis A1. The teeth can selectively interlock to maintain thebodies 302, 306 in one of a plurality of discrete rotational positionsrelative to one another.

As described further below, the hinge pin 310 can be formed integrallywith the first body 302. The hinge pin 310 can project laterally fromthe distal end 302 d of the first body 302 along the axis A1. Thebearing surface 330 of the first body 302 can be an exterior surface ofthe integrally-formed hinge pin 310.

The second body 302 is shown in greater detail in FIGS. 3C and 3H.Except as described below, the second body 306 can be identical orsubstantially identical to the first body 302, or can have any of thefeatures or variations described above with respect to the first body302. Accordingly, only a brief description of the second body 306 isprovided here for the sake of brevity. The second body 306 can includeproximal and distal ends 306 p, 306 d that define a proximal-distal axisA4. The proximal end 306 p of the body 306 can include a pair of spacedapart arms 334, 336 that define the second rod-receiving recess 308therebetween. A rod R2 disposed in the second rod-receiving recess 308can have a central longitudinal rod axis A5. The second rod-receivingrecess 308 can be open in a proximal direction, such that a rod R2 canbe inserted into the recess by moving the rod distally with respect tothe connector 300. Alternatively, the second rod-receiving recess 308can be open in distal direction, open in a lateral direction, or closedsuch that the rod R2 must be translated along the axis A5 to insert therod into the recess 308.

Each of the arms 334, 336 can include features 338 for retaining thesaddle 322 within the body 306, e.g., of the type described above withrespect to the connector 100. The second body 306 can include an outerbearing surface 340 configured to contact and bear against the outerbearing surface 330 of the first body 302. The distal end 306 d of thesecond body 306 can define an interior cavity 342 in which a free end ofthe hinge pin 310 can be received. The cavity 342 can be open to thebearing surface 340 of the second body 306 and open to the second rodrecess 308 as shown. In some embodiments, the cavity 342 can be a blindbore formed in the bearing surface 340 of the body 306 and intersectingwith the second rod recess 308. At least one dimension of the cavity 342can be greater than a corresponding dimension of the hinge pin 310 toallow the hinge pin to translate within the cavity along the rotationaxis A1.

The bodies 302, 306 of the connector 300 can include various featuresfor decreasing or increasing the center-to-center offset between thefirst and second rods R1, R2 when the rods are locked to the connector.For example, one or both of the outer surfaces of the bodies 302, 306that oppose one another can be obliquely angled with respect to therespective proximal-distal axes A2, A4. Accordingly, the rods R1, R2 canmove towards one another as they are advanced into the connector 300.This can advantageously reduce the center-to-center offset of the rodsR1, R2, while preserving sufficient material thickness at the proximalends of the bodies 302, 306 to withstand the relatively high forcessubjected to the connector 300 during rod reduction, fastenertightening, and/or post-operative patient movement.

As another example, the opposing outer surfaces of the bodies 302, 306can be parallel to the proximal-distal axes A2, A4, and instead the rodrecesses 304, 308 can be obliquely angled or can follow a curved pathwith respect to the proximal-distal axes to bring the rods R1, R2 closertogether.

As another example, the axis along which the first fastener 312 advancesas it is tightened can be offset laterally from the first rod axis A3when the first rod R1 is fully seated in the recess 304, or can beobliquely angled with respect to the proximal-distal axis A2 of thefirst body 302. Alternatively, or in addition, the axis along which thesecond fastener 314 advances as it is tightened can be offset laterallyfrom the second rod axis A5 when the second rod R2 is fully seated inthe recess 308, or can be obliquely angled with respect to theproximal-distal axis A4 of the second body 306.

The rotation axis A1 of the connector 300 can be perpendicular to therod axis A3 and perpendicular to the rod axis A5. The rotation axis A1can be perpendicular to the proximal-distal axis A2 of the first body,or can be obliquely angled with respect to the axis A2. The rotationaxis A1 can be perpendicular to the proximal-distal axis A4 of thesecond body, or can be obliquely angled with respect to the axis A4. Theproximal-distal axes A2, A4 of the bodies 302, 306 can be parallel toone another or can extend at an oblique angle with respect to oneanother.

The saddle 322 is shown in greater detail in FIGS. 3C, 3D, 3E, and 3F.The saddle 322 can be positioned within the body 306. The saddle 322 canbe configured to translate within the body 306 along the axis A4, e.g.,between proximal and distal limits defined by the interaction betweenthe recesses 338 of the body 306 and projections 356 formed on thesaddle.

The saddle 322 can be generally cylindrical with first and second arms358, 360 extending in a proximal direction to respective free ends ofthe arms. The first and second arms 358, 360 can be aligned with thefirst and second arms 334, 336 of the body 306 such that a recessdefined therebetween is aligned with the second rod-receiving recess308. Accordingly, the second rod R2 can be simultaneously cradledbetween the arms 358, 360 of the saddle 322 and the arms 334, 336 of thebody 306 when the rod is disposed in the second rod-receiving recess308. The first and second arms 358, 360 of the saddle 322 can includeprojections 356 extending radially outward therefrom and configured tobe received within the recesses 338 of the second body 306.

The distal-facing surface of the saddle 322 can define a recess 362configured to receive at least a portion of the hinge pin 310. In theillustrated embodiment, the recess 362 is semi-cylindrical. The depth ofthe recess 362 can increase along the length of the recess to accountfor a body geometry in which the proximal-distal axis A4 of the body 306is obliquely angled with respect to the rotation axis A1 of the hingepin 310.

The saddle 322 can include one or more ramped, curved, or otherwisetapered surfaces configured to contact and bear against a counterpartsurface of the hinge pin 310. For example, a keel projection 380extending distally from the recess 362 of the saddle 322 can define afirst bearing surface 366. The first bearing surface 366 can be planar.The first bearing surface 366 can lie in a plane that is obliquelyangled with respect to the rotation axis A1. As shown in FIG. 3F, thefirst bearing surface 366 can include first and second planar portionsthat are obliquely angled relative to one another and relative to theaxis A1, and that meet at a central ridge. This can facilitate smootherramping when the connector bodies 302, 306 are rotated relative to oneanother from a neutral position.

The first fastener 312 can include an exterior thread configured to matewith the interior threads formed on the arms 324, 326 of the body 302 toallow the first fastener to be advanced or retracted along the axis A2with respect to the body by rotating the first fastener about the axisA2. The first fastener 312 can include a driving interface 368configured to receive a driver for applying a rotational force to thefirst fastener about the axis A2. The distal surface of the firstfastener 312 can be configured to contact and bear against a rod R1disposed in the first rod-receiving 304 recess to lock the rod to theconnector 300. When tightened against the rod R1, the first fastener 312can prevent the rod from translating relative to the connector 300 alongthe axis A3 and/or from rotating with respect to the connector about theaxis A3. While a unitary set screw 312 is shown, it will be appreciatedthat other fasteners can be used instead or addition, such as a closurecap that advances and locks by quarter-turn rotation, a closure cap thatslides in laterally without rotating, or a nut that threads onto anexterior of the body.

The second fastener 314 can include an exterior thread configured tomate with the interior threads formed on the arms 334, 336 of the secondbody 306 to allow the second fastener to be advanced or retracted alongthe axis A4 with respect to the body by rotating the second fastenerabout the axis A4. The second fastener 314 can include a drivinginterface 370 configured to receive a driver for applying a rotationalforce to the second fastener 314 about the axis A4. The distal surfaceof the second fastener 314 can be configured to contact and bear againsta rod R2 disposed in the second rod-receiving 308 recess to lock the rodto the connector 300. When tightened against the rod R2, the secondfastener 314 can prevent the rod from translating relative to theconnector 300 along the axis A5 and/or from rotating with respect to theconnector about the axis A5. While a unitary set screw 314 is shown, itwill be appreciated that other fasteners can be used instead oraddition, such as a closure cap that advances and locks by quarter-turnrotation, a closure cap that slides in laterally without rotating, a nutthat threads onto an exterior of the body, or a dual-component set screwwith independently-rotatable inner and outer members, the inner memberacting on the rod R2 and the outer member acting on the saddle 322.

The hinge pin 310 can include opposed first and second ends that definea central longitudinal axis A6 extending therebetween. The longitudinalaxis A6 can be collinear with the rotation axis A1 of the connector 300.The hinge pin 310 can be formed integrally or monolithically with thefirst body 302 as shown, or can be fixedly attached thereto, e.g., bywelding or other processes. A free end of the hinge pin 310 can bereceived within the second body 306. The portion of the hinge pin 310received within the second body 306 can include a slot 382 formedtherein in which the keel 380 of the saddle 322 can be received. One ormore sidewalls of the slot 382 can be ramped, curved, or otherwisetapered and configured to contact and bear against a counterpart surfaceof the saddle 322 or, in embodiments in which the saddle 322 is omitted,against a counterpart surface of the second rod R2. The illustratedhinge pin 310 includes a ramped bearing surface 320 configured tocontact and bear against the bearing surface 366 of the saddle 322 asthe second fastener 314 is tightened. The bearing surface 320 can beplanar. The bearing surface 320 can lie in a plane that is obliquelyangled with respect to the rotation axis A1.

As the second fastener 314 is tightened, the saddle 322 can be urgeddistally to translate the keel 380 distally within the slot 382. As thekeel 380 moves within the slot 382, the bearing surface 366 of the keelcan be urged along the counterpart bearing surface 320 of the hinge pin310, causing the hinge pin to translate laterally within the cavity 342of the second body 306 along the axis A1, thereby pulling the first body302 towards the second body to lock relative rotation therebetween.

The distal end of the keel 380 can be tapered or bulleted to facilitateinsertion of the keel into the slot 382. Insertion of the keel 380 intothe slot 382 of the hinge pin 310 can prevent the hinge pin from beingremoved from the second body 306, thereby retaining the first and secondbodies 302, 306 to one another, even before one or both rods R1, R2 arelocked to the connector 300. Interaction between the keel 380 and theslot 382 can also be effective to limit the range of articulationbetween the first and second bodies 302, 306. For example, the slot 382can have a width in a direction perpendicular to the axis A1 andperpendicular to the axis A4 that is greater than a corresponding widthof the keel 380. The degree to which the bodies 302, 306 can rotaterelative to one another about the axis A1 can be limited by thedifference between the width of the slot 382 and the width of the keel380.

The connector 300 can be assembled by inserting the free end of thehinge pin 310 into the cavity 342 of the second body 306. The saddle 322can be inserted into the proximal end of the second body 306 andadvanced distally until the projections 356 of the saddle snap into thegrooves 338 of the second body 306 to retain the saddle therein. At thisstage of assembly, even before locking rods within the connector 300,the saddle 322 can interfere with the slot 382 of the hinge pin 310 toprevent the hinge pin from being removed from the second body 306.

A first rod R1 can be seated in the first rod recess 304 and secured tothe connector 300 by tightening the first fastener 312. The second body306 can remain free to rotate relative to the first body 302 about theaxis A1 even after the first rod R1 is locked to the connector 300.

A second rod R2 can be seated in the second rod recess 308 and securedto the connector 300 by tightening the second fastener 314. As thesecond fastener 314 is tightened, the second rod R2 can be urgeddistally against the saddle 322, in turn urging the saddle distallyagainst the hinge pin 310. As the saddle 322 is urged distally, theramped surface 366 of the saddle bears against the ramped surface 320 ofthe slot 382 in the hinge pin 310, applying a force to the hinge pinthat urges the hinge pin deeper into the cavity 342.

Before fully tightening one or both fasteners 312, 314, the bodies 302,306 can be rotated relative to one another about the axis A1 as desiredby the user. The fastener 314 can then be tightened to lock suchrelative rotation. In particular, the force applied to the hinge pin 310by the saddle 322 when the fastener 314 is tightened can cause thebodies 302, 306 to translate relative to one another along the axis A1,urging the bearing surfaces 330, 340 of the bodies into engagement witheach other. Friction, mechanical interlock, or other forces between thebearing surfaces 330, 340 can be effective to lock relative rotation ofthe bodies 302, 306 about the axis A1. It will be appreciated that theconnector 300 can allow locking of the first rod R1 to the connector andlocking of the rotational degree-of-freedom of the connector to beperformed independently of one another.

While a single, centrally-mounted keel 380 is described above, it willbe appreciated that other configurations are possible. For example, asshown in FIGS. 3I-3L, the saddle 322 can include first and second keels380A, 380B spaced apart from one another in the width dimension of thesaddle. As also shown, the slot of the hinge pin 310 can be replacedwith first and second slots 382A, 382B that form a reduced-width portionor central rib 384 of the hinge pin configured to be received betweenthe keels 380A, 380B of the saddle 322 when the connector 300 isassembled. Each keel 380A, 380B can include a ramped, curved, orotherwise tapered bearing surface that contacts and bears against acorresponding surface of the hinge pin 310 adjacent the central rib 384.The relative widths of the rib 384 and the space between the keels 380A,380B can be selected to limit the degree to which the first body 302 canrotate relative to the second body 306 about the axis A1.

FIGS. 4A-4F illustrate an exemplary embodiment of a connector 400. Asshown, the connector 400 can include a first body 402 that defines afirst rod-receiving recess or channel 404 and a second body 406 thatdefines a second rod-receiving recess or channel 408. The first andsecond bodies 402, 406 can be connected to one another at least in partby a hinge pin 410. The hinge pin 410 can define a rotation axis A1about which the first and second bodies 402, 406 can rotate relative toone another. The connector 400 can include first and second fasteners412, 414 configured to secure respective first and second rods R1, R2 orother fixation elements to the connector 400.

At least one of the fasteners 412, 414 can further be configured to urgethe first and second bodies 402, 406 towards one another and therebylock relative rotation of the first and second bodies about the rotationaxis A1. For example, the second fastener 414 can be tightened to securea second rod R2 within the second body 406 and to apply a force to aramped, curved, or otherwise tapered surface 420 of the hinge pin 410 todraw the first and second bodies 402, 406 towards one another, lockingrotation therebetween. In the illustrated embodiment, a force applied bythe second fastener 414 is transferred to the hinge pin 410 through thesecond rod R2. The first fastener 412 can be tightened to secure a firstrod R1 within the first body 402. The first fastener 412 can beardirectly against the first rod R1 as shown, or against an intermediaterod pusher of the type described above with respect to the connector200.

Except as indicated below and as will be readily appreciated by onehaving ordinary skill in the art in view of the present disclosure, thestructure and operation of the connector 400 is the same as theconnector 300 described above, and therefore a detailed description isomitted here for the sake of brevity.

As shown, the connector 400 can omit a saddle component, such that thesecond rod R2 bears directly against a rod seat 420 formed in the hingepin 410. The rod seat 420 can be ramped, curved, or otherwise tapered.The rod seat 420 can have a width parallel to the axis A1 that isgreater than the diameter of the second rod R2 and/or greater than thewidth of the second rod-receiving recess 408. The rod seat 420 can belocated along the length of the hinge pin 410 at a position in which alateral sidewall of the rod seat interferes with a rod R2 as the rod isseated in the second rod-receiving recess 408. As the rod R2 is advancedinto the second rod-receiving recess 408, it can bear against thelateral sidewall of the rod seat 420 to cause the hinge pin 410 totranslate along the axis A1, pulling the second body 406 towards thefirst body 402 to lock relative rotation therebetween.

The rod seat 420 can be curved in multiple planes to allow theabove-described bearing action to occur at any of a plurality ofrelative rotational positions about the axis A1 of the hinge pin 410 andthe second body 406. For example, the rod seat 420 can be curved in afirst plane defined by the axes A1, A2 and in a second plane defined bythe axes A2, A3. As shown in FIG. 4E, the rod seat can have a circularcross section in a first plane P1. As shown in FIG. 4F, the rod seat 420can have a cross section in a plane P2 perpendicular to the first planeP1 that is defined by first and second straight segments angled relativeto one another and joined by an arcuate segment.

The rod seat 420 can be configured such that approximately the same rampgeometry is presented to the rod R2, regardless of the articulationangle of the first and second bodies 402, 406. The degree of curvatureof the rod seat 420 in the second plane P2 can be configured to limitarticulation of the first and second bodies 402, 406.

The hinge pin 410 can be retained within the second body 406 usingvarious techniques, such as swaging or a retention pin that limits axialtranslation of the hinge pin relative to the body while still permittingrotation of the hinge pin relative to the second body. In theillustrated embodiment, the free end of the hinge pin 410 includes apost or rivet tail 486 that projects axially therefrom. The post 486 canbe received within a through-hole 488 formed in the second body 406 andthereafter swaged, deformed, flattened, or otherwise modified such thatthe post cannot be freely removed from the through-hole. The terminalend of the post 486 can be cupped or hollowed to facilitate deformationof the post during the swaging process.

Any of the connectors 100, 200, 300, 400 described above can include ataper-lock mating between the first and second bodies. The taper lockcan be formed by a conical male feature wedged into a conical femalefeature. The cone angle of the male feature can be in the range of about5 degrees to about 35 degrees. The cone angle of the male feature can beabout 20 degrees. The cone angle of the female feature can be in therange of about 5 degrees to about 35 degrees. The cone angle of thefemale feature can be about 20 degrees. The male and female conefeatures can have the same cone angle or different cone angles. Theconnector geometry can be selected such that there is a space betweenthe first and second bodies along the axis A1 when the connector isfully tightened, which can ensure that the taper lock bears most or allof the locking force. The male and female features can be flat cones, orcan include surface features such as axial splines.

The degree to which the first and second bodies can rotate relative toone another can vary in any of the connectors 100, 200, 300, 400described above. The first body can be rotatable up to 360 degrees withrespect to the second body. The first body can be rotatable up to about180 degrees with respect to the second body. The first body can berotatable up to about 60 degrees with respect to the second body.

The geometries of the rod-receiving recesses of any of the connectors100, 200, 300, 400 described above can vary. One or both recesses caninclude a V-shaped seat configured to accommodate rods of differentdiameters.

An exemplary method of using the connectors disclosed herein isdescribed below.

The procedure can begin by forming an open or percutaneous incision inthe patient to access a target site. The target site can be one or morevertebrae, a long bone or multiple portions of a long bone, or any otherbone or non-bone structure of the patient. As shown in FIG. 5, thetarget site can be multiple vertebrae in the patient's cervical andthoracic spine.

Bone anchors can be driven into one or more of the vertebrae and spinalrods can be attached thereto using known techniques. In the illustratedexample, bilateral spinal rods R1, R2 are coupled to four adjacentvertebrae V1-V4 using eight bone anchors S1-S8. In addition, bilateralrods R3, R4 are coupled to two additional vertebrae V5-V6 using fourbone anchors S9-S12. The rods R1, R2 can be connected to the rods R3,R4, respectively, using two connectors C1-C2 of the type describedherein (e.g., any of the connectors 100, 200, 300, 400 or combinationsor variations thereof).

The connectors C1-C2 can be articulated and locked in an articulatedposition as shown. This can allow the principal longitudinal axes of therods R1, R3 to be obliquely angled with respect to each other, and/orfor the principal longitudinal axes of the rods R2, R4 to be obliquelyangled with respect to each other.

All of the rods R1-R4, the connectors C1-C2, and the bone anchors S1-S12can be installed in a single procedure.

Alternatively, the rods R1, R2 and the bone anchors S1-S8 may have beeninstalled in a previous procedure, and the current procedure can be arevision procedure in which the rods R3, R4, the connectors C1-C2, andthe bone anchors S9-S12 are installed to extend the previously-installedconstruct to additional levels.

The connectors C1-C2 can be attached to position the rods R1-R4 suchthat they overlap in a lateral view. One or both connectors C1-C2 canalso be rotated 90 degrees from the orientation shown to position one orboth rod pairs R1, R3 and R2, R4 such that they overlap in a posterioror anterior view.

The above steps can be repeated to install additional rods and/orconnectors at the same or at different vertebral levels. Finaltightening or other adjustment of the construct can be performed and theprocedure can be completed using known techniques and the incisionclosed.

It should be noted that any ordering of method steps expressed orimplied in the description above or in the accompanying drawings is notto be construed as limiting the disclosed methods to performing thesteps in that order. Rather, the various steps of each of the methodsdisclosed herein can be performed in any of a variety of sequences. Inaddition, as the described methods are merely exemplary embodiments,various other methods that include additional steps or include fewersteps are also within the scope of the present disclosure.

While the methods illustrated and described herein generally involveattaching spinal rods to multiple vertebrae, it will be appreciated thatthe connectors and methods herein can be used with various other typesof fixation or stabilization hardware, in any bone, in non-bone tissue,or in non-living or non-tissue objects. The connectors disclosed hereincan be fully implanted, or can be used as part of an external fixationor stabilization system. The devices and methods disclosed herein can beused in minimally-invasive surgery and/or open surgery.

The devices disclosed herein and the various component parts thereof canbe constructed from any of a variety of known materials. Exemplarymaterials include those which are suitable for use in surgicalapplications, including metals such as stainless steel, titanium, oralloys thereof, polymers such as PEEK, ceramics, carbon fiber, and soforth. The various components of the devices disclosed herein can berigid or flexible. One or more components or portions of the device canbe formed from a radiopaque material to facilitate visualization underfluoroscopy and other imaging techniques, or from a radiolucent materialso as not to interfere with visualization of other structures. Exemplaryradiolucent materials include carbon fiber and high-strength polymers.

Although specific embodiments are described above, it should beunderstood that numerous changes may be made within the spirit and scopeof the concepts described.

The invention claimed is:
 1. A connector, comprising: a first body thatdefines a pair of spaced apart arms that define a first rod-receivingrecess therebetween, the first body having a proximal end and a distalend that define a first proximal-distal axis extending therebetween, thefirst rod-receiving recess having a rod-receiving opening formed in theproximal end of the first body; a second body that defines a secondrod-receiving recess, the second body having a proximal end and a distalend that define a second proximal-distal axis extending therebetween,the second rod-receiving recess having a rod-receiving opening formed inthe proximal end of the second body; a hinge pin that is one ofintegrally formed with the first body or fixedly attached to an outersurface of the first body that couples the first body to the secondbody, the hinge pin extending laterally from the first body to a freeend with a central longitudinal axis about which the first and secondbodies rotate relative to one another; a first fastener movable from theproximal end of the first body towards the distal end of the first bodyto secure a rod received within the first rod-receiving recess; and asecond fastener movable with respect to the second body to urge thefirst and second bodies towards one another along the centrallongitudinal axis and thereby lock relative rotation of the first andsecond bodies about the central longitudinal axis.
 2. The connector ofclaim 1, wherein the central longitudinal axis of the hinge pin istransverse to the first and second proximal-distal axes.
 3. Theconnector of claim 1, wherein the first proximal-distal axis isperpendicular to the central longitudinal axis of the hinge pin.
 4. Theconnector of claim 1, wherein the first proximal-distal axis and thesecond proximal-distal axis are parallel to one another.
 5. Theconnector of claim 1, wherein the first proximal-distal axis and thesecond proximal-distal axis extend at oblique angles relative to oneanother.
 6. The connector of claim 1, wherein the second fastener ismovable relative to the second rod-receiving recess to secure a rodreceived within the second rod-receiving recess.
 7. The connector ofclaim 1, wherein the free end of the hinge pin is received within acavity formed in the second body.
 8. The connector of claim 1, wherein aforce applied by the second fastener is transferred to the hinge pinthrough a saddle.
 9. The connector of claim 8, wherein the hinge pinincludes a slot formed therein and the saddle includes a distallyextending keel received within the slot of the hinge pin.
 10. Theconnector of claim 9, wherein the keel has a bearing surface thatengages and bears against a corresponding bearing surface of the slot topull the first and second bodies towards one another.
 11. The connectorof claim 10, wherein the bearing surfaces of the keel and the slot liein planes that are obliquely angled with respect to the centrallongitudinal axis.
 12. The connector of claim 8, wherein the saddleincludes first and second keels defining a space therebetween in which acentral rib of the hinge pin is received, the first and second keelshaving bearing surfaces that engage and bear against correspondingbearing surfaces of the hinge pin.
 13. The connector of claim 1, whereinthe free end of the hinge pin terminates within the second rod-receivingrecess.
 14. The connector of claim 1, wherein the first rod-receivingrecess is open in a proximal direction to allow a rod to be insertedinto the first rod-receiving recess by moving the rod distally into therod-receiving opening of the first body.
 15. A connector, comprising: afirst body that defines a first rod-receiving recess between a firstpair of spaced apart arms, the first body having a proximal end and adistal end that define a first proximal-distal axis extendingtherebetween and a first bearing surface, wherein the firstrod-receiving recess is configured to receive a first rod along thefirst proximal-distal axis; a second body that defines a secondrod-receiving recess between a second pair of spaced apart arms, thesecond body having a proximal end and a distal end that define a secondproximal-distal axis extending therebetween and a second bearing surfaceconfigured to contact and bear against the first bearing surface of thefirst body, wherein the second rod-receiving recess is configured toreceive a second rod along the second-proximal distal axis; a hinge pinextending laterally from the first body to a free end with a centrallongitudinal axis about which the first and second bodies rotaterelative to one another, the hinge pin being one of integrally formedwith the first body or fixedly attached to an outer surface of the firstbody; and a fastener received within the second body to urge the firstand second bodies towards one another along the central longitudinalaxis and thereby lock relative rotation of the first and second bodiesabout the central longitudinal axis, wherein the free end of the hingepin is received within a cavity formed in the second body to couple thesecond body to the first body.
 16. The connector of claim 15, whereinthe cavity formed in the second body intersects the second rod-receivingrecess.
 17. The connector of claim 15, wherein the cavity is a blindbore formed in the second body.
 18. The connector of claim 15, whereinthe first bearing surface and the second bearing surface bear againstone another to lock relative rotation between the first body and secondbody as the first body and the second body are urged towards oneanother.
 19. The connector of claim 15, wherein the first bearingsurface is an exterior surface of the hinge pin.
 20. The connector ofclaim 19, wherein the first bearing surface is a projection and thesecond bearing surface is a surface of an opening in the second bodyconfigured to receive the projection.
 21. The connector of claim 15,wherein at least one dimension of the cavity is greater than acorresponding dimension of the hinge pin such that the hinge pin cantranslate within the cavity along the central longitudinal axis.
 22. Theconnector of claim 15, wherein the second body includes a first armextending proximally from the distal end of the second body and a secondarm extending proximally from the distal end of the second body with thesecond rod-receiving recess formed therebetween, and wherein the cavityextends through one of the first and second arms without extendingthrough the other of the first and second arms.
 23. The connector ofclaim 15, wherein the first proximal-distal axis and the secondproximal-distal axis do not intersect.
 24. The connector of claim 15,wherein the first proximal-distal axis and the second proximal-distalaxis are perpendicular to the central longitudinal axis.
 25. Aconnector, comprising: a first body that defines a first rod-receivingrecess, the first body having a proximal end and a distal end thatdefine a first proximal-distal axis extending therebetween; a hinge pinextending laterally from the first body to a free end with a centrallongitudinal axis that is substantially transverse to the firstproximal-distal axis, the hinge pin being one of integrally formed withthe first body or fixedly attached to an outer surface of the first bodywith a slot formed therein; a second body that defines a secondrod-receiving recess, the second body having a proximal end and a distalend that define a second proximal-distal axis extending therebetween,the second body having a cavity that is configured to receive the hingepin therethrough to couple the first body to the second body; a saddlereceived in the second rod-receiving recess, the saddle having one ormore distally-extending projections that define a first bearing surface;wherein the hinge pin includes a slot that aligns with the secondproximal-distal axis when the first body is coupled to the second body,the slot being configured to receive the one or more distally-extendingprojections such that the first bearing surface is configured to contactand bear against a second bearing surface of the hinge pin to cause thehinge pin to translate laterally within the cavity of the second bodyalong the central longitudinal axis to lock relative rotation betweenthe first body and the second body.